Only skywatchers living in the Arctic witnessed last night’s aurora. All quiet here in the Midwest, where the auroral oval never budged from its comfort zone north of 55 degrees latitude.
John Chumack, Ohio astrophotographer, saw the sky go crazy. Last night he led an aurora photo tour and workshop near Fairbanks, Alaska. Tucked well within the oval at 65 degrees N his group witnessed a spectacular display of northern lights.
There were no alerts and no surprise electron-proton packages from the sun.Folks living in the far north can see the aurora almost every night of the year because they’re “under” or near the permanent cap of aurora called the northern auroral oval.
There’s also a southern version centered over Antarctica that can expand northward during solar storms to cast curtains of southern lights over southern South America and New Zealand.
Southern and northern ovals are similar in extent during both quiet and stormy times but not identical. Scientists discovered the disparity in data gathered by NASA’s Polar and IMAGE spacecraft (Imager for Magnetopause-to-Aurora Global Exploration) when the probes observed both ovals simultaneously in the early 2000s.
Come to find out, auroral ovals shift in opposite directions to each other depending on the orientation of the interplanetary magnetic field (IMF).
The IMF comes entangled in the steady stream of particles from the sun called the solar wind and possesses a magnetic field similar to the one in a simple bar magnet with north and south poles. Sometimes that field point south, sometimes north.
The ovals also shifted in opposite directions depending on how far the north magnetic pole (located in n. Canada) leaned toward the sun, making it easier at times for the solar wind to penetrate Earth’s magnetic bubble in the southern hemisphere than in the northern. This caused the southern oval to shift toward the sun and the northern to stay put.
“What was most surprising was that both the northern and southern auroral ovals were leaning toward the dawn (morning) side of the Earth for this event. The scientists suspect the leaning may be related to “imperfections” of the Earth’s magnetic field,” according to a NASA press release on the topic.
Although auroras are firing up again tonight over northern Scandinavia and Siberia, conditions are expected to remain “quiet” across the northern U.S. for at least the next two nights. I always take my forecasts with a grain of salt and pull the curtain back for a look anyway. Surprises are rampant when it comes to this stuff.